Differential inhibitory action of the fungal toxin orellanine on alkaline phosphatase isoenzymes

1989 ◽  
Vol 991 (2) ◽  
pp. 280-283 ◽  
Author(s):  
Christiane Ruedl ◽  
Gerhard Gstraunthaler ◽  
Meinhard Moser
Keyword(s):  
Alkaline Phosphatase ◽  
Inhibitory Action ◽  
Fungal Toxin ◽  
Alkaline Phosphatase Isoenzymes

Alkaline phosphatase. I. Kinetics and inhibition by levamisole of purified isoenzymes from humans.

1976 ◽  
Vol 22 (7) ◽  
pp. 972-976 ◽  
Author(s):  
H Van Belle
Keyword(s):  
Alkaline Phosphatase ◽  
Substrate Concentration ◽  
Human Liver ◽  
Alkaline Phosphatases ◽  
Mechanism Of Inhibition ◽  
Optimum Ph ◽  
Alkaline Phosphatase Isoenzymes

Abstract I studied the kinetics and sensitivity toward inhibition by levamisole and R 8231 of the most important human alkaline phosphatase isoenzymes. N-Ethylaminoethanol proved superior to the now widely used diethanolamine buffer, especially for the enzymes from the intestine and placenta, behaving as an uncompetitive activator. The optimum pH largely depends on the substrate concentration. The addition of Mg2+ has no effect on the activities. The meaning of Km-values for alkaline phosphatases is questioned. Isoenzymes from human liver, bone, kidney, and spleen are strongly inhibited by levamisole or R 8231 at concentrations that barely affect the enzymes from intestine or placenta. The inhibition is stereospecific, uncompetitive, and not changed by Mg2+. Inhibition is counteracted by increasing concentrations of N-ethylaminoethanol. The mechanism of inhibition is suggested to be formation of a complex with the phosphoenzyme.

Quantitative alkaline phosphatase isoenzyme determination by electrophoresis on cellulose acetate membranes.

1977 ◽  
Vol 23 (1) ◽  
pp. 28-34 ◽  
Author(s):  
W H Siede ◽  
U B Seiffert
Keyword(s):  
Alkaline Phosphatase ◽  
Cellulose Acetate ◽  
Clinical Laboratory ◽  
Kinetic Assay ◽  
Specific Staining ◽  
Cellulose Acetate Membranes ◽  
Alkaline Phosphatase Isoenzymes ◽  
Elution Method ◽  
Routine Clinical Laboratory ◽  
Alkaline Phosphatase Isoenzyme

Abstract We present a new method for quantitative determination of alkaline phosphatase isoenzymes. This method consists of electrophoretic separation on cellulose acetate membranes, special fixation technique to avoid elution and diffusion of enzyme protein during incubation, specific staining, and quantitative evaluation by densitometric measurement. We highly recommend the precedure for routine clinical laboratory use. In all normal individuals we observe two isoenzymes of hepatic origin and one isoenzyme each of osseous, intestinal, and biliary origin. Quantitative normal values are presented. Precision of the method is calculated, the CV being less than 10%. The exactness of densitometric quantification is proved by comparison with kinetic assay of alkaline phosphatase isoenzymes by use of an elution method. Clinical implications of alkaline phosphatase isoenzymograms are reported and discussed in detail.

scholarly journals Reaction Rate Retardation as a Method for Serum Alkaline Phosphatase Isoenzyme Measurement

1980 ◽  
Vol 17 (4) ◽  
pp. 192-198 ◽  
Author(s):  
Pamela B Brown ◽  
K O Lewis
Keyword(s):  
Alkaline Phosphatase ◽  
Reaction Rate ◽  
Serum Alkaline Phosphatase ◽  
Enzyme Reaction ◽  
Intestinal Alkaline Phosphatase ◽  
Wide Range ◽  
Alkaline Phosphatase Isoenzymes ◽  
Sensitivity And Selectivity ◽  
Rate Retardation ◽  
Alkaline Phosphatase Isoenzyme

A method for serum alkaline phosphatase isoenzymes using an enzyme reaction rate analyser is described. The complete urea-induced degradation of enzyme activity is monitored, from which individual isoenzyme activities are obtained by calculating the constituent exponential components of the degradation curve. Activities have been measured with adequate sensitivity and selectivity for up to four isoenzyme components in normal and in pathological sera. The identity of each isoenzyme present is assigned from its characteristic degradation half-life, and by this method bone and liver alkaline phosphatase are clearly distinguished and quantitated, and a composite value for placental-intestinal alkaline phosphatase activity is obtained. The approach promises to be applicable to a wide range of isoenzymes, and in analogy with ‘reaction rate’ the term ‘reaction rate retardation’ is suggested for the procedure.

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